1391977 has 8 divisors (see below), whose sum is σ = 1514376. Its totient is φ = 1274112.

The previous prime is 1391969. The next prime is 1391981. The reversal of 1391977 is 7791931.

It can be written as a sum of positive squares in 4 ways, for example, as 1125721 + 266256 = 1061^2 + 516^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1391977 - 2³ = 1391969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1391917) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 478 + ... + 1735.

It is an arithmetic number, because the mean of its divisors is an integer number (189297).

2^1391977 is an apocalyptic number.

1391977 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1391977 is a deficient number, since it is larger than the sum of its proper divisors (122399).

1391977 is a wasteful number, since it uses less digits than its factorization.

1391977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2267.

The product of its digits is 11907, while the sum is 37.

The square root of 1391977 is about 1179.8207490971. The cubic root of 1391977 is about 111.6547884695.

It can be divided in two parts, 139 and 1977, that added together give a square (2116 = 46²).

The spelling of 1391977 in words is "one million, three hundred ninety-one thousand, nine hundred seventy-seven".